/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
using System;
using java = biz.ritter.javapi;

using org.apache.commons.codec;

namespace org.apache.commons.codec.language
{

    /**
     * Encodes a string into a double metaphone value.
     * This Implementation is based on the algorithm by <CITE>Lawrence Philips</CITE>.
     * <ul>
     * <li>Original Article: <a 
     * href="http://www.cuj.com/documents/s=8038/cuj0006philips/">
     * http://www.cuj.com/documents/s=8038/cuj0006philips/</a></li>
     * <li>Original Source Code: <a href="ftp://ftp.cuj.com/pub/2000/1806/philips.zip">
     * ftp://ftp.cuj.com/pub/2000/1806/philips.zip</a></li>
     * </ul>
     * 
     * @author Apache Software Foundation
     * @version $Id: DoubleMetaphone.java 800153 2009-08-02 22:45:30Z ggregory $
     */
    public class DoubleMetaphone : StringEncoder
    {

        /**
         * "Vowels" to test for
         */
        private const String VOWELS = "AEIOUY";

        /**
         * Prefixes when present which are not pronounced
         */
        private static readonly String[] SILENT_START = new String[] { "GN", "KN", "PN", "WR", "PS" };
        private static readonly String[] L_R_N_M_B_H_F_V_W_SPACE = new String[] { "L", "R", "N", "M", "B", "H", "F", "V", "W", " " };
        private static readonly String[] ES_EP_EB_EL_EY_IB_IL_IN_IE_EI_ER = new String[] { "ES", "EP", "EB", "EL", "EY", "IB", "IL", "IN", "IE", "EI", "ER" };
        private static readonly String[] L_T_K_S_N_M_B_Z = new String[] { "L", "T", "K", "S", "N", "M", "B", "Z" };

        /**
         * Maximum length of an encoding, default is 4
         */
        protected int maxCodeLen = 4;

        /**
         * Creates an instance of this DoubleMetaphone encoder
         */
        public DoubleMetaphone()
            : base()
        {
        }

        /**
         * Encode a value with Double Metaphone
         *
         * @param value String to encode
         * @return an encoded string
         */
        public String doubleMetaphone(String value)
        {
            return doubleMetaphone(value, false);
        }

        /**
         * Encode a value with Double Metaphone, optionally using the alternate
         * encoding.
         *
         * @param value String to encode
         * @param alternate use alternate encode
         * @return an encoded string
         */
        public String doubleMetaphone(String value, bool alternate)
        {
            value = cleanInput(value);
            if (value == null)
            {
                return null;
            }

            bool slavoGermanic = isSlavoGermanic(value);
            int index = isSilentStart(value) ? 1 : 0;

            DoubleMetaphoneResult result = new DoubleMetaphoneResult(this.getMaxCodeLen(), this);

            while (!result.isComplete() && index <= value.length() - 1)
            {
                switch (value.charAt(index))
                {
                    case 'A':
                    case 'E':
                    case 'I':
                    case 'O':
                    case 'U':
                    case 'Y':
                        index = handleAEIOUY(value, result, index);
                        break;
                    case 'B':
                        result.append('P');
                        index = charAt(value, index + 1) == 'B' ? index + 2 : index + 1;
                        break;
                    case '\u00C7':
                        // A C with a Cedilla
                        result.append('S');
                        index++;
                        break;
                    case 'C':
                        index = handleC(value, result, index);
                        break;
                    case 'D':
                        index = handleD(value, result, index);
                        break;
                    case 'F':
                        result.append('F');
                        index = charAt(value, index + 1) == 'F' ? index + 2 : index + 1;
                        break;
                    case 'G':
                        index = handleG(value, result, index, slavoGermanic);
                        break;
                    case 'H':
                        index = handleH(value, result, index);
                        break;
                    case 'J':
                        index = handleJ(value, result, index, slavoGermanic);
                        break;
                    case 'K':
                        result.append('K');
                        index = charAt(value, index + 1) == 'K' ? index + 2 : index + 1;
                        break;
                    case 'L':
                        index = handleL(value, result, index);
                        break;
                    case 'M':
                        result.append('M');
                        index = conditionM0(value, index) ? index + 2 : index + 1;
                        break;
                    case 'N':
                        result.append('N');
                        index = charAt(value, index + 1) == 'N' ? index + 2 : index + 1;
                        break;
                    case '\u00D1':
                        // N with a tilde (spanish ene)
                        result.append('N');
                        index++;
                        break;
                    case 'P':
                        index = handleP(value, result, index);
                        break;
                    case 'Q':
                        result.append('K');
                        index = charAt(value, index + 1) == 'Q' ? index + 2 : index + 1;
                        break;
                    case 'R':
                        index = handleR(value, result, index, slavoGermanic);
                        break;
                    case 'S':
                        index = handleS(value, result, index, slavoGermanic);
                        break;
                    case 'T':
                        index = handleT(value, result, index);
                        break;
                    case 'V':
                        result.append('F');
                        index = charAt(value, index + 1) == 'V' ? index + 2 : index + 1;
                        break;
                    case 'W':
                        index = handleW(value, result, index);
                        break;
                    case 'X':
                        index = handleX(value, result, index);
                        break;
                    case 'Z':
                        index = handleZ(value, result, index, slavoGermanic);
                        break;
                    default:
                        index++;
                        break;
                }
            }

            return alternate ? result.getAlternate() : result.getPrimary();
        }

        /**
         * Encode the value using DoubleMetaphone.  It will only work if 
         * <code>obj</code> is a <code>String</code> (like <code>Metaphone</code>).
         *
         * @param obj Object to encode (should be of type String)
         * @return An encoded Object (will be of type String)
         * @throws EncoderException encode parameter is not of type String
         */
        public Object encode(Object obj)
        {// throws EncoderException {
            if (obj is java.lang.StringJ) obj = ((java.lang.StringJ)obj).ToString();
            if (!(obj is String))
            {
                throw new EncoderException("DoubleMetaphone encode parameter is not of type String");
            }
            return doubleMetaphone((String)obj);
        }

        /**
         * Encode the value using DoubleMetaphone.
         *
         * @param value String to encode
         * @return An encoded String
         */
        public String encode(String value)
        {
            return doubleMetaphone(value);
        }

        /**
         * Check if the Double Metaphone values of two <code>String</code> values
         * are equal.
         * 
         * @param value1 The left-hand side of the encoded {@link String#equals(Object)}.
         * @param value2 The right-hand side of the encoded {@link String#equals(Object)}.
         * @return <code>true</code> if the encoded <code>String</code>s are equal;
         *          <code>false</code> otherwise.
         * @see #isDoubleMetaphoneEqual(String,String,bool)
         */
        public bool isDoubleMetaphoneEqual(String value1, String value2)
        {
            return isDoubleMetaphoneEqual(value1, value2, false);
        }

        /**
         * Check if the Double Metaphone values of two <code>String</code> values
         * are equal, optionally using the alternate value.
         * 
         * @param value1 The left-hand side of the encoded {@link String#equals(Object)}.
         * @param value2 The right-hand side of the encoded {@link String#equals(Object)}.
         * @param alternate use the alternate value if <code>true</code>.
         * @return <code>true</code> if the encoded <code>String</code>s are equal;
         *          <code>false</code> otherwise.
         */
        public bool isDoubleMetaphoneEqual(String value1,
                                              String value2,
                                              bool alternate)
        {
            return doubleMetaphone(value1, alternate).equals(doubleMetaphone
                                                             (value2, alternate));
        }

        /**
         * Returns the maxCodeLen.
         * @return int
         */
        public int getMaxCodeLen()
        {
            return this.maxCodeLen;
        }

        /**
         * Sets the maxCodeLen.
         * @param maxCodeLen The maxCodeLen to set
         */
        public void setMaxCodeLen(int maxCodeLen)
        {
            this.maxCodeLen = maxCodeLen;
        }

        //-- BEGIN HANDLERS --//

        /**
         * Handles 'A', 'E', 'I', 'O', 'U', and 'Y' cases
         */
        private int handleAEIOUY(String value, DoubleMetaphoneResult result, int
                                 index)
        {
            if (index == 0)
            {
                result.append('A');
            }
            return index + 1;
        }

        /**
         * Handles 'C' cases
         */
        private int handleC(String value,
                            DoubleMetaphoneResult result,
                            int index)
        {
            if (conditionC0(value, index))
            {  // very confusing, moved out
                result.append('K');
                index += 2;
            }
            else if (index == 0 && contains(value, index, 6, "CAESAR"))
            {
                result.append('S');
                index += 2;
            }
            else if (contains(value, index, 2, "CH"))
            {
                index = handleCH(value, result, index);
            }
            else if (contains(value, index, 2, "CZ") &&
                     !contains(value, index - 2, 4, "WICZ"))
            {
                //-- "Czerny" --//
                result.append('S', 'X');
                index += 2;
            }
            else if (contains(value, index + 1, 3, "CIA"))
            {
                //-- "focaccia" --//
                result.append('X');
                index += 3;
            }
            else if (contains(value, index, 2, "CC") &&
                     !(index == 1 && charAt(value, 0) == 'M'))
            {
                //-- double "cc" but not "McClelland" --//
                return handleCC(value, result, index);
            }
            else if (contains(value, index, 2, "CK", "CG", "CQ"))
            {
                result.append('K');
                index += 2;
            }
            else if (contains(value, index, 2, "CI", "CE", "CY"))
            {
                //-- Italian vs. English --//
                if (contains(value, index, 3, "CIO", "CIE", "CIA"))
                {
                    result.append('S', 'X');
                }
                else
                {
                    result.append('S');
                }
                index += 2;
            }
            else
            {
                result.append('K');
                if (contains(value, index + 1, 2, " C", " Q", " G"))
                {
                    //-- Mac Caffrey, Mac Gregor --//
                    index += 3;
                }
                else if (contains(value, index + 1, 1, "C", "K", "Q") &&
                         !contains(value, index + 1, 2, "CE", "CI"))
                {
                    index += 2;
                }
                else
                {
                    index++;
                }
            }

            return index;
        }

        /**
         * Handles 'CC' cases
         */
        private int handleCC(String value,
                             DoubleMetaphoneResult result,
                             int index)
        {
            if (contains(value, index + 2, 1, "I", "E", "H") &&
                !contains(value, index + 2, 2, "HU"))
            {
                //-- "bellocchio" but not "bacchus" --//
                if ((index == 1 && charAt(value, index - 1) == 'A') ||
                    contains(value, index - 1, 5, "UCCEE", "UCCES"))
                {
                    //-- "accident", "accede", "succeed" --//
                    result.append("KS");
                }
                else
                {
                    //-- "bacci", "bertucci", other Italian --//
                    result.append('X');
                }
                index += 3;
            }
            else
            {    // Pierce's rule
                result.append('K');
                index += 2;
            }

            return index;
        }

        /**
         * Handles 'CH' cases
         */
        private int handleCH(String value,
                             DoubleMetaphoneResult result,
                             int index)
        {
            if (index > 0 && contains(value, index, 4, "CHAE"))
            {   // Michael
                result.append('K', 'X');
                return index + 2;
            }
            else if (conditionCH0(value, index))
            {
                //-- Greek roots ("chemistry", "chorus", etc.) --//
                result.append('K');
                return index + 2;
            }
            else if (conditionCH1(value, index))
            {
                //-- Germanic, Greek, or otherwise 'ch' for 'kh' sound --//
                result.append('K');
                return index + 2;
            }
            else
            {
                if (index > 0)
                {
                    if (contains(value, 0, 2, "MC"))
                    {
                        result.append('K');
                    }
                    else
                    {
                        result.append('X', 'K');
                    }
                }
                else
                {
                    result.append('X');
                }
                return index + 2;
            }
        }

        /**
         * Handles 'D' cases
         */
        private int handleD(String value,
                            DoubleMetaphoneResult result,
                            int index)
        {
            if (contains(value, index, 2, "DG"))
            {
                //-- "Edge" --//
                if (contains(value, index + 2, 1, "I", "E", "Y"))
                {
                    result.append('J');
                    index += 3;
                    //-- "Edgar" --//
                }
                else
                {
                    result.append("TK");
                    index += 2;
                }
            }
            else if (contains(value, index, 2, "DT", "DD"))
            {
                result.append('T');
                index += 2;
            }
            else
            {
                result.append('T');
                index++;
            }
            return index;
        }

        /**
         * Handles 'G' cases
         */
        private int handleG(String value,
                            DoubleMetaphoneResult result,
                            int index,
                            bool slavoGermanic)
        {
            if (charAt(value, index + 1) == 'H')
            {
                index = handleGH(value, result, index);
            }
            else if (charAt(value, index + 1) == 'N')
            {
                if (index == 1 && isVowel(charAt(value, 0)) && !slavoGermanic)
                {
                    result.append("KN", "N");
                }
                else if (!contains(value, index + 2, 2, "EY") &&
                         charAt(value, index + 1) != 'Y' && !slavoGermanic)
                {
                    result.append("N", "KN");
                }
                else
                {
                    result.append("KN");
                }
                index = index + 2;
            }
            else if (contains(value, index + 1, 2, "LI") && !slavoGermanic)
            {
                result.append("KL", "L");
                index += 2;
            }
            else if (index == 0 && (charAt(value, index + 1) == 'Y' || contains(value, index + 1, 2, ES_EP_EB_EL_EY_IB_IL_IN_IE_EI_ER)))
            {
                //-- -ges-, -gep-, -gel-, -gie- at beginning --//
                result.append('K', 'J');
                index += 2;
            }
            else if ((contains(value, index + 1, 2, "ER") ||
                      charAt(value, index + 1) == 'Y') &&
                     !contains(value, 0, 6, "DANGER", "RANGER", "MANGER") &&
                     !contains(value, index - 1, 1, "E", "I") &&
                     !contains(value, index - 1, 3, "RGY", "OGY"))
            {
                //-- -ger-, -gy- --//
                result.append('K', 'J');
                index += 2;
            }
            else if (contains(value, index + 1, 1, "E", "I", "Y") ||
                     contains(value, index - 1, 4, "AGGI", "OGGI"))
            {
                //-- Italian "biaggi" --//
                if ((contains(value, 0, 4, "VAN ", "VON ") || contains(value, 0, 3, "SCH")) || contains(value, index + 1, 2, "ET"))
                {
                    //-- obvious germanic --//
                    result.append('K');
                }
                else if (contains(value, index + 1, 3, "IER"))
                {
                    result.append('J');
                }
                else
                {
                    result.append('J', 'K');
                }
                index += 2;
            }
            else if (charAt(value, index + 1) == 'G')
            {
                index += 2;
                result.append('K');
            }
            else
            {
                index++;
                result.append('K');
            }
            return index;
        }

        /**
         * Handles 'GH' cases
         */
        private int handleGH(String value,
                             DoubleMetaphoneResult result,
                             int index)
        {
            if (index > 0 && !isVowel(charAt(value, index - 1)))
            {
                result.append('K');
                index += 2;
            }
            else if (index == 0)
            {
                if (charAt(value, index + 2) == 'I')
                {
                    result.append('J');
                }
                else
                {
                    result.append('K');
                }
                index += 2;
            }
            else if ((index > 1 && contains(value, index - 2, 1, "B", "H", "D")) ||
                     (index > 2 && contains(value, index - 3, 1, "B", "H", "D")) ||
                     (index > 3 && contains(value, index - 4, 1, "B", "H")))
            {
                //-- Parker's rule (with some further refinements) - "hugh"
                index += 2;
            }
            else
            {
                if (index > 2 && charAt(value, index - 1) == 'U' &&
                    contains(value, index - 3, 1, "C", "G", "L", "R", "T"))
                {
                    //-- "laugh", "McLaughlin", "cough", "gough", "rough", "tough"
                    result.append('F');
                }
                else if (index > 0 && charAt(value, index - 1) != 'I')
                {
                    result.append('K');
                }
                index += 2;
            }
            return index;
        }

        /**
         * Handles 'H' cases
         */
        private int handleH(String value,
                            DoubleMetaphoneResult result,
                            int index)
        {
            //-- only keep if first & before vowel or between 2 vowels --//
            if ((index == 0 || isVowel(charAt(value, index - 1))) &&
                isVowel(charAt(value, index + 1)))
            {
                result.append('H');
                index += 2;
                //-- also takes car of "HH" --//
            }
            else
            {
                index++;
            }
            return index;
        }

        /**
         * Handles 'J' cases
         */
        private int handleJ(String value, DoubleMetaphoneResult result, int index,
                            bool slavoGermanic)
        {
            if (contains(value, index, 4, "JOSE") || contains(value, 0, 4, "SAN "))
            {
                //-- obvious Spanish, "Jose", "San Jacinto" --//
                if ((index == 0 && (charAt(value, index + 4) == ' ') ||
                     value.length() == 4) || contains(value, 0, 4, "SAN "))
                {
                    result.append('H');
                }
                else
                {
                    result.append('J', 'H');
                }
                index++;
            }
            else
            {
                if (index == 0 && !contains(value, index, 4, "JOSE"))
                {
                    result.append('J', 'A');
                }
                else if (isVowel(charAt(value, index - 1)) && !slavoGermanic &&
                            (charAt(value, index + 1) == 'A' || charAt(value, index + 1) == 'O'))
                {
                    result.append('J', 'H');
                }
                else if (index == value.length() - 1)
                {
                    result.append('J', ' ');
                }
                else if (!contains(value, index + 1, 1, L_T_K_S_N_M_B_Z) && !contains(value, index - 1, 1, "S", "K", "L"))
                {
                    result.append('J');
                }

                if (charAt(value, index + 1) == 'J')
                {
                    index += 2;
                }
                else
                {
                    index++;
                }
            }
            return index;
        }

        /**
         * Handles 'L' cases
         */
        private int handleL(String value,
                            DoubleMetaphoneResult result,
                            int index)
        {
            if (charAt(value, index + 1) == 'L')
            {
                if (conditionL0(value, index))
                {
                    result.appendPrimary('L');
                }
                else
                {
                    result.append('L');
                }
                index += 2;
            }
            else
            {
                index++;
                result.append('L');
            }
            return index;
        }

        /**
         * Handles 'P' cases
         */
        private int handleP(String value,
                            DoubleMetaphoneResult result,
                            int index)
        {
            if (charAt(value, index + 1) == 'H')
            {
                result.append('F');
                index += 2;
            }
            else
            {
                result.append('P');
                index = contains(value, index + 1, 1, "P", "B") ? index + 2 : index + 1;
            }
            return index;
        }

        /**
         * Handles 'R' cases
         */
        private int handleR(String value,
                            DoubleMetaphoneResult result,
                            int index,
                            bool slavoGermanic)
        {
            if (index == value.length() - 1 && !slavoGermanic &&
                contains(value, index - 2, 2, "IE") &&
                !contains(value, index - 4, 2, "ME", "MA"))
            {
                result.appendAlternate('R');
            }
            else
            {
                result.append('R');
            }
            return charAt(value, index + 1) == 'R' ? index + 2 : index + 1;
        }

        /**
         * Handles 'S' cases
         */
        private int handleS(String value,
                            DoubleMetaphoneResult result,
                            int index,
                            bool slavoGermanic)
        {
            if (contains(value, index - 1, 3, "ISL", "YSL"))
            {
                //-- special cases "island", "isle", "carlisle", "carlysle" --//
                index++;
            }
            else if (index == 0 && contains(value, index, 5, "SUGAR"))
            {
                //-- special case "sugar-" --//
                result.append('X', 'S');
                index++;
            }
            else if (contains(value, index, 2, "SH"))
            {
                if (contains(value, index + 1, 4,
                             "HEIM", "HOEK", "HOLM", "HOLZ"))
                {
                    //-- germanic --//
                    result.append('S');
                }
                else
                {
                    result.append('X');
                }
                index += 2;
            }
            else if (contains(value, index, 3, "SIO", "SIA") || contains(value, index, 4, "SIAN"))
            {
                //-- Italian and Armenian --//
                if (slavoGermanic)
                {
                    result.append('S');
                }
                else
                {
                    result.append('S', 'X');
                }
                index += 3;
            }
            else if ((index == 0 && contains(value, index + 1, 1, "M", "N", "L", "W")) || contains(value, index + 1, 1, "Z"))
            {
                //-- german & anglicisations, e.g. "smith" match "schmidt" //
                // "snider" match "schneider" --//
                //-- also, -sz- in slavic language altho in hungarian it //
                //   is pronounced "s" --//
                result.append('S', 'X');
                index = contains(value, index + 1, 1, "Z") ? index + 2 : index + 1;
            }
            else if (contains(value, index, 2, "SC"))
            {
                index = handleSC(value, result, index);
            }
            else
            {
                if (index == value.length() - 1 && contains(value, index - 2,
                                                            2, "AI", "OI"))
                {
                    //-- french e.g. "resnais", "artois" --//
                    result.appendAlternate('S');
                }
                else
                {
                    result.append('S');
                }
                index = contains(value, index + 1, 1, "S", "Z") ? index + 2 : index + 1;
            }
            return index;
        }

        /**
         * Handles 'SC' cases
         */
        private int handleSC(String value,
                             DoubleMetaphoneResult result,
                             int index)
        {
            if (charAt(value, index + 2) == 'H')
            {
                //-- Schlesinger's rule --//
                if (contains(value, index + 3,
                             2, "OO", "ER", "EN", "UY", "ED", "EM"))
                {
                    //-- Dutch origin, e.g. "school", "schooner" --//
                    if (contains(value, index + 3, 2, "ER", "EN"))
                    {
                        //-- "schermerhorn", "schenker" --//
                        result.append("X", "SK");
                    }
                    else
                    {
                        result.append("SK");
                    }
                }
                else
                {
                    if (index == 0 && !isVowel(charAt(value, 3)) && charAt(value, 3) != 'W')
                    {
                        result.append('X', 'S');
                    }
                    else
                    {
                        result.append('X');
                    }
                }
            }
            else if (contains(value, index + 2, 1, "I", "E", "Y"))
            {
                result.append('S');
            }
            else
            {
                result.append("SK");
            }
            return index + 3;
        }

        /**
         * Handles 'T' cases
         */
        private int handleT(String value,
                            DoubleMetaphoneResult result,
                            int index)
        {
            if (contains(value, index, 4, "TION"))
            {
                result.append('X');
                index += 3;
            }
            else if (contains(value, index, 3, "TIA", "TCH"))
            {
                result.append('X');
                index += 3;
            }
            else if (contains(value, index, 2, "TH") || contains(value, index,
                                                                 3, "TTH"))
            {
                if (contains(value, index + 2, 2, "OM", "AM") ||
                    //-- special case "thomas", "thames" or germanic --//
                    contains(value, 0, 4, "VAN ", "VON ") ||
                    contains(value, 0, 3, "SCH"))
                {
                    result.append('T');
                }
                else
                {
                    result.append('0', 'T');
                }
                index += 2;
            }
            else
            {
                result.append('T');
                index = contains(value, index + 1, 1, "T", "D") ? index + 2 : index + 1;
            }
            return index;
        }

        /**
         * Handles 'W' cases
         */
        private int handleW(String value,
                            DoubleMetaphoneResult result,
                            int index)
        {
            if (contains(value, index, 2, "WR"))
            {
                //-- can also be in middle of word --//
                result.append('R');
                index += 2;
            }
            else
            {
                if (index == 0 && (isVowel(charAt(value, index + 1)) ||
                                   contains(value, index, 2, "WH")))
                {
                    if (isVowel(charAt(value, index + 1)))
                    {
                        //-- Wasserman should match Vasserman --//
                        result.append('A', 'F');
                    }
                    else
                    {
                        //-- need Uomo to match Womo --//
                        result.append('A');
                    }
                    index++;
                }
                else if ((index == value.length() - 1 && isVowel(charAt(value, index - 1))) ||
                         contains(value, index - 1,
                                  5, "EWSKI", "EWSKY", "OWSKI", "OWSKY") ||
                         contains(value, 0, 3, "SCH"))
                {
                    //-- Arnow should match Arnoff --//
                    result.appendAlternate('F');
                    index++;
                }
                else if (contains(value, index, 4, "WICZ", "WITZ"))
                {
                    //-- Polish e.g. "filipowicz" --//
                    result.append("TS", "FX");
                    index += 4;
                }
                else
                {
                    index++;
                }
            }
            return index;
        }

        /**
         * Handles 'X' cases
         */
        private int handleX(String value,
                            DoubleMetaphoneResult result,
                            int index)
        {
            if (index == 0)
            {
                result.append('S');
                index++;
            }
            else
            {
                if (!((index == value.length() - 1) &&
                      (contains(value, index - 3, 3, "IAU", "EAU") ||
                       contains(value, index - 2, 2, "AU", "OU"))))
                {
                    //-- French e.g. breaux --//
                    result.append("KS");
                }
                index = contains(value, index + 1, 1, "C", "X") ? index + 2 : index + 1;
            }
            return index;
        }

        /**
         * Handles 'Z' cases
         */
        private int handleZ(String value, DoubleMetaphoneResult result, int index,
                            bool slavoGermanic)
        {
            if (charAt(value, index + 1) == 'H')
            {
                //-- Chinese pinyin e.g. "zhao" or Angelina "Zhang" --//
                result.append('J');
                index += 2;
            }
            else
            {
                if (contains(value, index + 1, 2, "ZO", "ZI", "ZA") || (slavoGermanic && (index > 0 && charAt(value, index - 1) != 'T')))
                {
                    result.append("S", "TS");
                }
                else
                {
                    result.append('S');
                }
                index = charAt(value, index + 1) == 'Z' ? index + 2 : index + 1;
            }
            return index;
        }

        //-- BEGIN CONDITIONS --//

        /**
         * Complex condition 0 for 'C'
         */
        private bool conditionC0(String value, int index)
        {
            if (contains(value, index, 4, "CHIA"))
            {
                return true;
            }
            else if (index <= 1)
            {
                return false;
            }
            else if (isVowel(charAt(value, index - 2)))
            {
                return false;
            }
            else if (!contains(value, index - 1, 3, "ACH"))
            {
                return false;
            }
            else
            {
                char c = charAt(value, index + 2);
                return (c != 'I' && c != 'E') ||
                        contains(value, index - 2, 6, "BACHER", "MACHER");
            }
        }

        /**
         * Complex condition 0 for 'CH'
         */
        private bool conditionCH0(String value, int index)
        {
            if (index != 0)
            {
                return false;
            }
            else if (!contains(value, index + 1, 5, "HARAC", "HARIS") &&
                     !contains(value, index + 1, 3, "HOR", "HYM", "HIA", "HEM"))
            {
                return false;
            }
            else if (contains(value, 0, 5, "CHORE"))
            {
                return false;
            }
            else
            {
                return true;
            }
        }

        /**
         * Complex condition 1 for 'CH'
         */
        private bool conditionCH1(String value, int index)
        {
            return ((contains(value, 0, 4, "VAN ", "VON ") || contains(value, 0,
                                                                       3, "SCH")) ||
                    contains(value, index - 2, 6, "ORCHES", "ARCHIT", "ORCHID") ||
                    contains(value, index + 2, 1, "T", "S") ||
                    ((contains(value, index - 1, 1, "A", "O", "U", "E") || index == 0) &&
                     (contains(value, index + 2, 1, L_R_N_M_B_H_F_V_W_SPACE) || index + 1 == value.length() - 1)));
        }

        /**
         * Complex condition 0 for 'L'
         */
        private bool conditionL0(String value, int index)
        {
            if (index == value.length() - 3 &&
                contains(value, index - 1, 4, "ILLO", "ILLA", "ALLE"))
            {
                return true;
            }
            else if ((contains(value, value.length() - 2, 2, "AS", "OS") ||
                      contains(value, value.length() - 1, 1, "A", "O")) &&
                     contains(value, index - 1, 4, "ALLE"))
            {
                return true;
            }
            else
            {
                return false;
            }
        }

        /**
         * Complex condition 0 for 'M'
         */
        private bool conditionM0(String value, int index)
        {
            if (charAt(value, index + 1) == 'M')
            {
                return true;
            }
            return contains(value, index - 1, 3, "UMB") &&
                    ((index + 1) == value.length() - 1 || contains(value,
                            index + 2, 2, "ER"));
        }

        //-- BEGIN HELPER FUNCTIONS --//

        /**
         * Determines whether or not a value is of slavo-germanic orgin. A value is
         * of slavo-germanic origin if it contians any of 'W', 'K', 'CZ', or 'WITZ'.
         */
        private bool isSlavoGermanic(String value)
        {
            return value.indexOf('W') > -1 || value.indexOf('K') > -1 ||
                value.indexOf("CZ") > -1 || value.indexOf("WITZ") > -1;
        }

        /**
         * Determines whether or not a character is a vowel or not
         */
        private bool isVowel(char ch)
        {
            return VOWELS.indexOf(ch) != -1;
        }

        /**
         * Determines whether or not the value starts with a silent letter.  It will
         * return <code>true</code> if the value starts with any of 'GN', 'KN',
         * 'PN', 'WR' or 'PS'.
         */
        private bool isSilentStart(String value)
        {
            bool result = false;
            for (int i = 0; i < SILENT_START.Length; i++)
            {
                if (value.startsWith(SILENT_START[i]))
                {
                    result = true;
                    break;
                }
            }
            return result;
        }

        /**
         * Cleans the input
         */
        private String cleanInput(String input)
        {
            if (input == null)
            {
                return null;
            }
            input = input.trim();
            if (input.length() == 0)
            {
                return null;
            }
            return input.toUpperCase(java.util.Locale.ENGLISH);
        }

        /**
         * Gets the character at index <code>index</code> if available, otherwise
         * it returns <code>Character.MIN_VALUE</code> so that there is some sort
         * of a default
         */
        protected char charAt(String value, int index)
        {
            if (index < 0 || index >= value.length())
            {
                return java.lang.Character.MIN_VALUE;
            }
            return value.charAt(index);
        }

        /**
         * Shortcut method with 1 criteria
         */
        private static bool contains(String value, int start, int length,
                                        String criteria)
        {
            return contains(value, start, length,
                            new String[] { criteria });
        }

        /**
         * Shortcut method with 2 criteria
         */
        private static bool contains(String value, int start, int length,
                                        String criteria1, String criteria2)
        {
            return contains(value, start, length,
                            new String[] { criteria1, criteria2 });
        }

        /**
         * Shortcut method with 3 criteria
         */
        private static bool contains(String value, int start, int length,
                                        String criteria1, String criteria2,
                                        String criteria3)
        {
            return contains(value, start, length,
                            new String[] { criteria1, criteria2, criteria3 });
        }

        /**
         * Shortcut method with 4 criteria
         */
        private static bool contains(String value, int start, int length,
                                        String criteria1, String criteria2,
                                        String criteria3, String criteria4)
        {
            return contains(value, start, length,
                            new String[] { criteria1, criteria2, criteria3, 
                                       criteria4 });
        }

        /**
         * Shortcut method with 5 criteria
         */
        private static bool contains(String value, int start, int length,
                                        String criteria1, String criteria2,
                                        String criteria3, String criteria4,
                                        String criteria5)
        {
            return contains(value, start, length,
                            new String[] { criteria1, criteria2, criteria3, 
                                       criteria4, criteria5 });
        }

        /**
         * Shortcut method with 6 criteria
         */
        private static bool contains(String value, int start, int length,
                                        String criteria1, String criteria2,
                                        String criteria3, String criteria4,
                                        String criteria5, String criteria6)
        {
            return contains(value, start, length,
                            new String[] { criteria1, criteria2, criteria3, 
                                       criteria4, criteria5, criteria6 });
        }

        /**
         * Determines whether <code>value</code> contains any of the criteria starting at index <code>start</code> and
         * matching up to length <code>length</code>
         */
        protected static bool contains(String value, int start, int length,
                                          String[] criteria)
        {
            bool result = false;
            if (start >= 0 && start + length <= value.length())
            {
                String target = value.substring(start, start + length);

                for (int i = 0; i < criteria.Length; i++)
                {
                    if (target.equals(criteria[i]))
                    {
                        result = true;
                        break;
                    }
                }
            }
            return result;
        }

        //-- BEGIN INNER CLASSES --//

        /**
         * Inner class for storing results, since there is the optional alternate
         * encoding.
         */
        public class DoubleMetaphoneResult
        {

            private java.lang.StringBuffer primary;
            private java.lang.StringBuffer alternate;
            private int maxLength;

            private readonly DoubleMetaphone root;

            public DoubleMetaphoneResult(int maxLength, DoubleMetaphone root)
            {
                this.root = root;
                this.primary = new java.lang.StringBuffer(root.getMaxCodeLen());
                this.alternate = new java.lang.StringBuffer(root.getMaxCodeLen());
                this.maxLength = maxLength;
            }

            public void append(char value)
            {
                appendPrimary(value);
                appendAlternate(value);
            }

            public void append(char primary, char alternate)
            {
                appendPrimary(primary);
                appendAlternate(alternate);
            }

            public void appendPrimary(char value)
            {
                if (this.primary.length() < this.maxLength)
                {
                    this.primary.append(value);
                }
            }

            public void appendAlternate(char value)
            {
                if (this.alternate.length() < this.maxLength)
                {
                    this.alternate.append(value);
                }
            }

            public void append(String value)
            {
                appendPrimary(value);
                appendAlternate(value);
            }

            public void append(String primary, String alternate)
            {
                appendPrimary(primary);
                appendAlternate(alternate);
            }

            public void appendPrimary(String value)
            {
                int addChars = this.maxLength - this.primary.length();
                if (value.length() <= addChars)
                {
                    this.primary.append(value);
                }
                else
                {
                    this.primary.append(value.substring(0, addChars));
                }
            }

            public void appendAlternate(String value)
            {
                int addChars = this.maxLength - this.alternate.length();
                if (value.length() <= addChars)
                {
                    this.alternate.append(value);
                }
                else
                {
                    this.alternate.append(value.substring(0, addChars));
                }
            }

            public String getPrimary()
            {
                return this.primary.toString();
            }

            public String getAlternate()
            {
                return this.alternate.toString();
            }

            public bool isComplete()
            {
                return this.primary.length() >= this.maxLength &&
                    this.alternate.length() >= this.maxLength;
            }
        }
    }
}